restrict.m

五点差分型多重网格方法：各种插值算子的比较）

function coarse_resid = restrict(level, resid)

% Ryan McKenzie
% Department of Computational Sciences
% University of Kentucky

amg_globals;

if SETUP_OPT==AT_EACH
    amg_setup(level);
end

%generate coarse grid residual
coarse_resid = W(level).weight' * resid;